Cutting tool

A cutting tool comprising:

• a body in which a discharge groove for guiding and discharging chips is formed so as to extend from a distal end side toward a proximal end side;
• and
• a cutting insert fastened and fixed on the distal end side of the body, wherein
• the cutting insert has
• a first surface through which a through-hole for inserting a fastening member is opened,
• a second surface that is opposite the first surface and contacts an insert seat of the body, and
• a major cutting edge that is formed so as to extend straight at an end part of the first surface and at least part of which is used for cutting,
• the cutting insert is fastened and fixed to the body by the fastening member such that the first surface faces inward of the discharge groove and the major cutting edge protrudes on the distal end side of a distal end of the body,
• a protrusion portion protruding so as to cover part of the first surface of the cutting insert from outside is formed at the body,
• the cutting insert includes
• a first corner cutting edge connected to an outer periphery side end part of the major cutting edge, and
• a second corner cutting edge positioned opposite the first corner cutting edge along a diagonal line of the first surface,
• the second corner cutting edge is covered by the protrusion portion,
• a clearance hole for preventing contact with the second corner cutting edge is formed in the body, and
• the clearance hole is formed so as to extend from a surface of the body opposite the cutting insert toward the second corner cutting edge when viewed from the distal end side along a central axis of the body.